Method of making piston rings



D. W. HAMM Feb. 2, 1954 METHOD OF MAKING PISTON RINGS 2 Sheets-Sheet 1 Filed March 8, 1952 /nven for Doug/0s W. Hamm Feb. 2, 1954 D. w. HAMM 2,668,131

METHOD OF MAKING PISTON "RINGS Filed March 8, 1952 2 Sheets-Sheet 2 fl'g. L3.

\ l J I .-/,8 /nvenf0r Doug/asl V. Hamm Af/omey Patented Feb. 2, 1954 2,668,131 I METHOD OF MAKING PISTON RINGS Douglas W. Hamm, Muskegon, Mich., assignor to Muskegon Piston Ring Company, Muskegon, -Mich., a corporation of Michigan Application March 8, 1952, Serial No. 275,515 b 1 This invention relates to a novel and very practical and'useful method of producing a circumferentially compressible piston ring. The compressible ring, usually of thin spring-like metal has been known for a considerabl time, and the practice employed in making it requires a blanking or shearing operation to outline and produce a continuous series of segmental sections, one at the upper side of the ring and one at the lower side thereof, the segments in the completed ring, having a very considerable degree of independent action in connection with the total ring action. As the edges of the blank of the material used for the ring are straight, and as such edges become the outside edges of the ring, the ring must be ground or finished circular on the outside diameter after forming in order to change, from a chord to an arc, the edges of those parts of the segments which contact the cylinder wall. With my invention the ring is formed in circular form before dividing or separating the consecutive series of segmental sections. Thereafter, the ring flanges or lands which are in circular form and are continuous in length are broken or fractured transversely at selected proper points in the length to obtain the final structur of generally independent land segments or sections.

No material is removed in such breaking.

The breaking is accomplished preferably by heat treating the formed ring, which is of a proper ferrous composition that it may be hardened, so that the material is of a hardness of approximately 65 Rockwell scale. Such material is brittle, or, as it is known, glass hard and slight impact or pressure causes the ring to break in th exact locations desired which may, preferably, be preselected by grooving or notching the material at one side where the breaks are to occur..

After breaking has been done, the ring is then heat treated to reduce the hardness so that it will have desired physical properties and characteristics. As the ring has been formed circularly, no grinding on the outside diameter is required. Rings having narrow lands can be practically produced by having the proper narrow width stocksto start with. In my invention and the method used, accurate control of the closure gap of a parted ring is maintained, and the gaps or spaces between consecutive ring segments may be made smaller than has previously been practical..,

The invention is useable not only to make pa e ir l mi rent a ly o r ler nss ut.

7 Claims. (01. 148-424) also rings which are continuous having no partings scoring breaking lines of the material to or 7 toward the outer edges thereof.

Figs. 3 and a are fragmentary longitudinal sections substantially on the planes of lines 3-3.

and 44 of Fig. 2.

Fig. 5 is a fragmentary perspective view of a portion of a length of the ring after the side flanges have been turned at right angles to the connecting web portions thereof.

Fig. 6 is a plan View, partly in dash line; and i with the remainder partly in plan and partly in intermediate horizontal section of the formed circular ring which is produced, after the second step of the operation to produce the ring flanges as in Fig. 5.

Fig. is a fragmentary enlarged outer edge elevation of the formed ring shown in Fig. 6 before breaking the flanges into a consecutive series of land segments.

Fig. 8 is a like view after such breaking, which i is preferably substantially upon the notched or scored grooves between the outer edges of the ring and the openings therethrough.

Fig. 9 is a partial plan and partial intermediate longitudinal section, enlarged, through a fragmentary portion of the completed ring after the segment breaking separation.

Fig. 10 is an elevation showing the first step of operation of producing a circular grooved continuous ring from tubular stock.

Fig. 11 is a similar elevation showing the manner in which such circular ring having the channel cross section is cut from the tube. V

Fig. 12 is a plan view showing the circular ring in outline after the succeeding step of the operation, which consists in milling separated vertical slots in the inside diameter web of the rings cut from the tubular stock, and providing the notched or depressed breaking grooves therein,

and

Figs. l3 and 14 are views similar to Figs. 7 and I 3 8 showing inner elevations of fragmentary portions of the ring, the one before the segment separation by breaking has occurred, and the other after it has taken place.

Like reference characters refer to like parts in the different figures of the drawings.

With my method, the length of net thin metal ribbon stock indicated {at' i'l whichniay be ofthe; length of'orfe ring, butin practice" i generally elongated so as to produce a plurality of rings which may be separated one from the other, is" first subjected to punching o erationswo stnke" therefrom elongated transverse ope gitudinally spaced from each, ends inwardly of the oppositd of metal l. Alternate openings 2 at op'fi ends thereof also, preferably; have shallow grooves 3 pressed therein extending fromselected ends of the openings 2 with which assdciatedto" the adjacent longitudinaredge of the metalstrip It Betwen successive grooves 3 at "botl'r' side; edges of the ring there will be defined segments bj wiiat in tlifcoi'ripleted ring w n he connectin SbXtndin'g betweithe'segments'l at oppos'it eiaes of the ring: H V i J Th rlat nietalstrip-brocess described and n in Fig; 2', is thereafter formed intoa arfofi ln' and-with the 'flongitudinal sidei edge turned iiith s'ain direction'froin the I g wb 5% p i'allel each other, making a'--subs"tantially continuous circular channel in whiclifth "onnect ihg'web portions Scat the inner curved sire" (if-the chaniiel are separated from each other by the opnin 4 A'ftfithrfiihirear: ed the circular 'for m substantially as in 'Fi'g. 6, it" is heat treated and quenched so that the material whiich i preferafilf'ofafrelativelyhigh calrbon's't'eel having substa ritially ,90 o cai boficonterit (not'necess'arily closely restricted'tlieretoi isjf m ay havea hardnssj wll flC scare-. isf radi ly 'brolreh byfl I V the gfoovest. Evn'fthe grooves'are dt 'useil thebfeaking will occur in" the narrower widths Of tHe -material between" the ends of the slots ,21 and the adjacent edges of theformed circular- The are are siicaeseive and s ee n em lii I having the proper carbon content, rings of channel cross section are successively out, each having a groove 9 which is first machined by a proper cutting tool ID before the ring is separated from the tube 8 by a cutting tool H, the groove 9 being between opposed annular flanges i z of, the channel shaped ring ,S uch ring havii g p p rti g; isj then ill Yiatliit'sl'in rjer side to ciit a' consecutive series of spaced slots 2 extending between the flanges, the slots being cut through the web of the channel ring form and 1eaviiig weii' partiuns 5 between the segmental portions g whic vith this way of making the ecfat their ends by similar M from opposite ends of alterna 9 sl ts 2 tethe outer edges of the channel sfd'e's'-l2."' Said-grooves 3 can be made at the outer sides of t he flanges l2 as well as at the inner sidesT and will provide weakened breaking lines Th iious'iring h type installed o r'af p s to' bylst 30 it; over the piston insteadjof the presen c tionaliinsifallation of siire ading theffends apart and placing it thering'groovof a piston} Y r.

4 ir te teed thussebarted isiagainlheatftreated} proper Q QWm ae 1 Q l-,. t esa esen ineer coin tcigether'and abut at a partinggjindicated I ie'teutnig in its-'fre'estate being larger than thej pressed to reduce its outside aiamaerena 'cl'os e' th' 'gai1s"at'fi"to "substaintia1ly combletly closed position. U m rig'sa io 5 11" ana 12; from a tube 8 "of "st and lower ends extending into the flanges at the inner portions thereof, heat treating and quenching said ring member to harden it to brittle, easily fractured condition, fracturing each flange from its outer edge to the adjacent ends of alternate slots, the fractures in one flange being staggered with respect to the fractures in the other flange, and again heat treating the rin member to reduce hardness thereof.

3. The method of making a circumferentially compressible piston ring consistin in, providing a circular ring member of thin steel material of channel cross section having upper and lower parallel, continuous horizontal flanges and an integral, generally vertical connecting web between said flanges, said web having a continuous and consecutive series of openings spaced lengthwise of the web, with web connecting portions between said openings connecting said flanges, heat treating and quenching the ring member to harden it to a brittle easily fractured condition, fracturing each flange transversely from its free edge to adjacent openings, and again heat treating the ring member to reduce its hardness.

4. The method having the process steps defined in claim 2, and stretchin the ring member circumferentially after the last heat treatment thereof.

' 5. The method having the process steps defined in claim 3, and widening the breaks in said, flanges where fractured, after the last heat treatment of the ring member.

6. The method having the process steps defined in claim 3, and weakening the metal in the said flanges, at preselected points in the flanges where fracture thereof is wanted, before the first heat treatment and hardening of the ring member.

7. The method of making a circumferentially compressible piston ring consisting in, removing from a thin elongated strip of steel ribbon material having parallel side edges, metal in an elongated zone substantially midway between the side edges to make a consecutive series of spaced openings, in length substantially at right angles the length of the strip, bending the side edge portions of the strip in the same direction and the entire strip into substantially circular channel cross sectional form, having continuous spaced flanges to provide a ring member, heating and quenching the ring member to harden it to a brittle, easily fractured condition, fracturing said flanges from the outer edges thereof to the adjacent ends of alternate openings, the fractures in one flange being staggered with respect to the fractures in the other flange, and again heatin said ring member to reduce hardness thereof.

DOUGLAS W. HAMM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,887,504 Frost Nov. 15, 1932 1,997,534 Oubridge Apr. 9, 1935 2,346,898 Bowers Apr. 18, 1944 

1. THE METHOD OF MAKING A CIRCUMFERENTIALLY COMPRESSIBLE PISTON RING CONSISTING IN, PROVIDING A CIRCULAR RING MEMBER OF THIN STEEL MATERIAL OF CHANNEL CROSS SECTION, HAVING UPPER AND LOWER SPACED PARALLEL CONTINUOUS HORIZONTAL FLANGES AND A VERTICAL CONNECTING WEB, SAID WEB HAVING A SUCCESSIVE SERIES OF CLOSELY SPACED GENERALLY VERTICAL SLOTS, WITH GENERALLY VERTICAL WEB PORTIONS BETWEEN SAID SLOTS, HEAT TREATING AND HARDENING SAID MEMBER TO A BRITTLE, EASILY FRACTURED CONDITION, FRACTURING EACH FLANGE FROM ITS FREE EDGE TO THE ADJACENT ENDS OF ALTERNATE SLOTS, AND THEREAFTER AGAIN HEAT TREATING THE RING MEMBER TO REDUCE HARDNESS THEREOF. 